Analysis of secondary growth in the Arabidopsis shoot reveals a positive role of jasmonate signalling in cambium formation.

After primary growth, most dicotyledonous plants undergo secondary growth. Secondary growth involves an increase in the diameter of shoots and roots through formation of secondary vascular tissue. A hallmark of secondary growth initiation in shoots of dicotyledonous plants is the initiation of meristematic activity between primary vascular bundles, i.e. in the interfascicular regions. This results in establishment of a cylindrical meristem, namely the vascular cambium. Surprisingly, despite its major implications for plant growth and the accumulation of biomass, the molecular regulation of secondary growth is only poorly understood. Here, we combine histological, molecular and genetic approaches to characterize interfascicular cambium initiation in the Arabidopsis thaliana inflorescence shoot. Using genome-wide transcriptional profiling, we show that stress-related and touch-inducible genes are up-regulated in stem regions where secondary growth takes place. Furthermore, we show that the products of COI1, MYC2, JAZ7 and the touch-inducible gene JAZ10, which are components of the JA signalling pathway, are cambium regulators. The positive effect of JA application on cambium activity confirmed a stimulatory role of JA in secondary growth, and suggests that JA signalling triggers cell divisions in this particular context.

Formation of the long range Dpp morphogen gradient.

The TGF-β homolog Decapentaplegic (Dpp) acts as a secreted morphogen in the Drosophila wing disc, and spreads through the target tissue in order to form a long range concentration gradient. Despite extensive studies, the mechanism by which the Dpp gradient is formed remains controversial. Two opposing mechanisms have been proposed: receptor-mediated transcytosis (RMT) and restricted extracellular diffusion (RED). In these scenarios the receptor for Dpp plays different roles. In the RMT model it is essential for endocytosis, re-secretion, and thus transport of Dpp, whereas in the RED model it merely modulates Dpp distribution by binding it at the cell surface for internalization and subsequent degradation. Here we analyzed the effect of receptor mutant clones on the Dpp profile in quantitative mathematical models representing transport by either RMT or RED. We then, using novel genetic tools, experimentally monitored the actual Dpp gradient in wing discs containing receptor gain-of-function and loss-of-function clones. Gain-of-function clones reveal that Dpp binds in vivo strongly to the type I receptor Thick veins, but not to the type II receptor Punt. Importantly, results with the loss-of-function clones then refute the RMT model for Dpp gradient formation, while supporting the RED model in which the majority of Dpp is not bound to Thick veins. Together our results show that receptor-mediated transcytosis cannot account for Dpp gradient formation, and support restricted extracellular diffusion as the main mechanism for Dpp dispersal. The properties of this mechanism, in which only a minority of Dpp is receptor-bound, may facilitate long-range distribution.

ATP release due to Thy-1-integrin binding induces P2X7-mediated calcium entry required for focal adhesion formation.

Thy-1, an abundant mammalian glycoprotein, interacts with αvβ3 integrin and syndecan-4 in astrocytes and thus triggers signaling events that involve RhoA and its effector p160ROCK, thereby increasing astrocyte adhesion to the extracellular matrix. The signaling cascade includes calcium-dependent activation of protein kinase Cα upstream of Rho; however, what causes the intracellular calcium transients required to promote adhesion remains unclear. Purinergic P2X7 receptors are important for astrocyte function and form large non-selective cation pores upon binding to their ligand, ATP. Thus, we evaluated whether the intracellular calcium required for Thy-1-induced cell adhesion stems from influx mediated by ATP-activated P2X7 receptors. Results show that adhesion induced by the fusion protein Thy-1-Fc was preceded by both ATP release and sustained intracellular calcium elevation. Elimination of extracellular ATP with Apyrase, chelation of extracellular calcium with EGTA, or inhibition of P2X7 with oxidized ATP, all individually blocked intracellular calcium increase and Thy-1-stimulated adhesion. Moreover, Thy-1 mutated in the integrin-binding site did not trigger ATP release, and silencing of P2X7 with specific siRNA blocked Thy-1-induced adhesion. This study is the first to demonstrate a functional link between αvβ3 integrin and P2X7 receptors, and to reveal an important, hitherto unanticipated, role for P2X7 in calcium-dependent signaling required for Thy-1-stimulated astrocyte adhesion.

The Hippo Transducer YAP1 Transforms Activated Satellite Cells and Is a Potent Effector of Embryonal Rhabdomyosarcoma Formation.

The role of the Hippo pathway effector YAP1 in soft tissue sarcomas is poorly defined. Here we report that YAP1 activity is elevated in human embryonal rhabdomyosarcoma (ERMS). In mice, sustained YAP1 hyperactivity in activated, but not quiescent, satellite cells induces ERMS with high penetrance and short latency. Via its transcriptional program with TEAD1, YAP1 directly regulates several major hallmarks of ERMS. YAP1-TEAD1 upregulate pro-proliferative and oncogenic genes and maintain the ERMS differentiation block by interfering with MYOD1 and MEF2 pro-differentiation activities. Normalization of YAP1 expression reduces tumor burden in human ERMS xenografts and allows YAP1-driven ERMS to differentiate in situ. Collectively, our results identify YAP1 as a potent ERMS oncogenic driver and a promising target for differentiation therapy.

Analysis of past and future dam formation and failure in the Santa Cruz River (San Juan province, Argentina)

Around 11.5 * 106 m3 of rock detached from the eastern slope of the Santa Cruz valley (San Juan province, Argentina) in the first fortnight of January 2005. The rockslide?debris avalanche blocked the course, resulting in the development of a lake with maximum length of around 3.5 km. The increase in the inflow rate from 47,000?74,000 m3/d between April and October to 304,000 m3/d between late October and the first fortnight of November, accelerated the growing rate of the lake. On 12 November 2005 the dam failed, releasing 24.6 * 106 m3 of water. The resulting outburst flood caused damages mainly on infrastructure, and affected the facilities of a hydropower dam which was under construction 250 km downstream from the source area. In this work we describe causes and consequences of the natural dam formation and failure, and we dynamically model the 2005 rockslide?debris avalanche with DAN3D. Additionally, as a volume ~ 24 * 106 m3of rocks still remain unstable in the slope, we use the results of the back analysis to forecast the formation of a future natural dam. We analyzed two potential scenarios: a partial slope failure of 6.5 * 106 m3 and a worst case where all the unstable volume remaining in the slope fails. The spreading of those potential events shows that a new blockage of the Santa Cruz River is likely to occur. According to their modeled morphometry and the contributing watershed upstream the blockage area, as the one of 2005, the dams would also be unstable. This study shows the importance of back and forward analysis that can be carried out to obtain critical information for land use planning, hazards mitigation, and emergency management.

As TIC enquanto instrumentos da Comunicação Organizacional - O caso do NOSI

Este trabalho tem como objectivo analisar o papel das TIC dentro do processo organizacional, tendo como estudo de caso o NOSI – Núcleo Operacional para a Sociedade de Informação. O uso das TIC hoje em dia tem-se tornado cada vez mais presente no seio das organizações, que estão cada vez mais a apostar na eficiência, para poderem atingir os seus objectivos, acompanhar o mercado que está cada vez mais competitivo, e dar respostas em tempo real e num curto espaço de tempo. Por isso, é extremamente importante o uso das TIC dentro do processo organizacional. No actual contexto é natural que as organizações recorram às TIC como forma de terem os seus negócios bem sucedidos no mercado, tirando e trazendo vantagem também para a comunicação interna como externa. As TIC não são meros instrumentos que circulam no local do trabalho, mas sim novos suportes tecnológicos que tornam mais fácil o acesso à comunicação e à informação, nomeadamente pela velocidade e rapidez e encurtando as distâncias. O estudo pretende ainda demonstrar o papel das TIC no seio de uma organização. Neste caso a organização em estudo é o NOSI. Tratando-se de um estudo qualitativo, os métodos utilizados foram o inquérito por questionário. O trabalho divide-se em três capítulos, sendo dois de enquadramento teórico e um prático no qual se inclui o estudo de caso, onde se abordam os assuntos com mais profundidade.

A member of the PLEIOTROPIC DRUG RESISTANCE family of ATP binding cassette transporters is required for the formation of a functional cuticle in Arabidopsis.

Although the multilayered structure of the plant cuticle was discovered many years ago, the molecular basis of its formation and the functional relevance of the layers are not understood. Here, we present the permeable cuticle1 (pec1) mutant of Arabidopsis thaliana, which displays features associated with a highly permeable cuticle in several organs. In pec1 flowers, typical cutin monomers, such as ω-hydroxylated fatty acids and 10,16-dihydroxypalmitate, are reduced to 40% of wild-type levels and are accompanied by the appearance of lipidic inclusions within the epidermal cell. The cuticular layer of the cell wall, rather than the cuticle proper, is structurally altered in pec1 petals. Therefore, a significant role for the formation of the diffusion barrier in petals can be attributed to this layer. Thus, pec1 defines a new class of mutants. The phenotypes of the pec1 mutant are caused by the knockout of ATP BINDING CASSETTEG32 (ABCG32), an ABC transporter from the PLEIOTROPIC DRUG RESISTANCE family that is localized at the plasma membrane of epidermal cells in a polar manner toward the surface of the organs. Our results suggest that ABCG32 is involved in the formation of the cuticular layer of the cell wall, most likely by exporting particular cutin precursors from the epidermal cell.

Necessidade de Formação Contínua dos Professores para Utilização das Tic na Escola Um Estudo com Professores de uma Escola Secundária em Cabo Verde

No momento em que se verifica algumas reformas no sistema educativo cabo-verdiano, torna-se necessário analisar a questão da formação dos professores de forma a prepará-los para a função que têm que desempenhar. Com a realização deste estudo, pretende-se diagnosticar percursos e necessidade de formação dos professores na área das Tecnologias de Informação e Comunicação (TIC), bem como descrever o sentido de competência (auto-eficácia) dos professores na utilização das tecnologias, concretamente à mobilização dos mesmos no processo ensino e aprendizagem. Tendo em conta os objetivos do estudo, optou-se por utilizar uma metodologia de natureza quantitativa. O estudo integra a participação de 87 professores. Escolheu-se a técnica de inquérito, realizando um inquérito por questionário com questões fechadas aos professores da Escola Secundária Abílio Duarte situada na Cidade da Praia, ilha de Santiago, Cabo Verde. A revisão da literatura permitiu verificar que já foram desenvolvidas iniciativas, a nível nacional, para a implementação das TIC nas escolas. Atualmente destaca-se o programa Mundu Novu do governo de Cabo Verde, coordenado pelo Ministério da Educação, que tem como objetivo modernizar o processo de ensino através da utilização das TIC criando um novo paradigma de ensino interativo. Os resultados apontam para a progressiva utilização das TIC nas atividades dos professores que revelam um moderado sentido de auto-eficácia de utilização das TIC. A formação de professores é apontada como o principal obstáculo à integração e utilização educativa das TIC.

The cdc7 protein kinase is a dosage dependent regulator of septum formation in fission yeast.

Mutation of the Schizosaccharomyces pombe cdc7 gene prevents formation of the division septum and cytokinesis. We have cloned the cdc7 gene and show that it encodes a protein kinase which is essential for cell division. In the absence of cdc7 function, spore germination, DNA synthesis and mitosis are unaffected, but cells are unable to initiate formation of the division septum. Overexpression of p120cdc7 causes cell cycle arrest; cells complete mitosis and then undergo multiple rounds of septum formation without cell cleavage. This phenotype, which is similar to that resulting from inactivation of cdc16 protein, requires the kinase activity of p120cdc7. Mutations inactivating the early septation gene, cdc11, suppress the formation of multiple septa and allow cells to proliferate normally. If formation of the division septum is prevented by inactivation of either cdc14 or cdc15, p120cdc7 overproduction does not interfere with other events in the mitotic cell cycle. Septation is not induced by overexpression of p120cdc7 in G2 arrested cells, indicating that it does not bypass the normal dependency of septation upon initiation of mitosis. These findings indicate that the p120cdc7 protein kinase plays a key role in initiation of septum formation and cytokinesis in fission yeast and suggest that p120cdc7 interacts with the cdc11 protein in the control of septation.

Ex post bargaining, labor coordination and wage formation at the firm level

We lay out a model of wage bargaining with two leading features:bargaining is ex post to relevant investments and there isindividual bargaining in firms without a Union. We compareindividual ex post bargaining to coordinated ex post bargainingand we analyze the effects on wage formation. As opposed to exante bargaining models, the costs of destroying the employmentrelationship play a crucial role in determining wages. Highfiring costs in particular yield a rent for employees. Ourtheory points to a employer size-wage effect that is independentof the production function and market power. We derive a simpleleast squares specification from the theoretical model thatallow us to estimate components of the wage premium fromcoordination. We reject the hypothesis that labor coordinationdoes not alter the extensive form of the bargaining game. Laborcoordination substantially increases bargaining power butdecreases labor's ability to pose costly threats to the firm.

Contributo das TIC na integração de famílias oriundas do Brasil no concelho de Albufeira

Os fenómenos migratórios tem-se acentuado nas últimas décadas, para este facto muito tem contribuído a era globalizada em que nos encontramos. Com a globalização surgiu o desenvolvimento de redes mundiais, nomeadamente sistemas sociais e económicos, facultando o acesso a meios de transporte mais rápidos e baratos, e as comunicações tornaram-se mais fáceis, promovendo e facilitando as deslocações entre países e continentes, de pessoas e bens. Assim, actualmente com o acesso facilitado nas comunicações e nas deslocações, a migração tornou-se uma constante. Perante a quantidade de indivíduos oriundos das mais diversas partes do globo e com a evolução das tecnologias de informação e comunicação, as barreiras culturais foram reduzidas, permitindo uma rápida difusão de ideias e de meios, possibilitando que indivíduos que se encontram em locais geograficamente longínquos possam comunicar com regularidade. Este estudo teve como objectivo conhecer, por um lado, o impacto da utilização das TIC, por parte dos imigrantes de origem brasileira, como forma de manterem o contacto com o país de origem, por outro, o facto de residirem familiares/amigos em Portugal, aquando da sua vinda, podem contribuir para a sua integração. O estudo foi aplicado no Gabinete da família e no Gabinete do Imigrante, da Divisão de Acção Social Saúde e Juventude, da Câmara Municipal de Albufeira. Teve uma amostragem por conveniência que abrangeu 50 indivíduos oriundos do Brasil, residentes em Albufeira. Foi aplicado um inquérito por questionário que permitiu a caracterização da amostra e recolher informações sobre o impacto da utilização das TIC como forma de manter o contacto com o país de origem e a importância das redes sociais no processo de integração. Constituído por 74 questões fechadas, abertas e semi abertas. Fez-se de seguida uma análise quantitativa e qualitativa dos dados recolhidos. Os resultados obtidos sobre esta problemática permitiram percepcionar que o facto de existir uma rede familiar e de amigos, contribui para a integração da família imigrante na sociedade de acolhimento. Ou seja, todo o suporte familiar e a rede de amigos existente facultam ao imigrante condições para que o mesmo se instale no país de acolhimento e se sinta integrado. O facto de os imigrantes comunicarem, por norma, semanalmente com a família no Brasil, bem como utilizarem as tecnologias de informação e comunicação, contribui em muito para o seu bem estar psicológico e emocional. O contacto regular com a família, ainda que através de uma Web cam, proporciona-lhes tranquilidade e minimiza a distância física, uma vez que os podem ver e ouvir sentindo assim o apoio dos mesmos, ajudando-os a permanecer no nosso país. O uso das novas tecnologias são utilizadas para manter a ligação com a comunidade de origem, fomentando os laços familiares e com amigos. Os imigrantes utilizam a internet para comunicar com os indivíduos da mesma nacionalidade, bem como a família/amigos que se encontram no Brasil. O acesso às TIC e o facto de as utilizarem para comunicar com a família e amigos, no país de origem, pode ser considerada como uma rede social de apoio, proporcionando assim aos imigrantes uma integração no país de acolhimento.

Capital formation in machinery in Latin America, 1890-1930

Investment in machinery is a key aspect in the analysis of long-term economic growth during the era of the spread of industrialisation. But, historiography has only revealed what the pace of capital accumulation was in a few Latin American economies. This article offers continuous (annual) and consistent series on the magnitude of this investment in all of the Latin American countries for the period at the height of the first globalisation, 1890-1930. The paper gives special attention to comparative analysis, showing the differences that exist at the heart of the Latin American community, in the levels of capital formation in machinery as well as in the national development of this over time. The differences in the levels appear very indicative of the unequal degree of development reached by these economies. This article puts to test the hypothesis of intraregional divergence, obtaining the tentative result that there was divergence until 1913, but that there was convergence from 1914-1930.